The prior art is replete with many categories of exercise machines designed to exercise all major muscle groups of the human body. The most popular machines provide motion similar to activities such as bicycling, skiing, walking or stepping. Machines such as stationary bicycles cause the operator's feet to move under resistance along constrained arcuate paths created by the simple relationship of the distance between the foot pedal and the pedal crank shaft. This constancy of motion is artificial to the human body, and is not considered by the inventor to be optimum during exclusive use for long term muscular development and conditioning. As compared to stepper machines, on the other hand, bicycle machines do offer a continuous motion which is preferable in order to ensure extended machine usage.
In reference to stepper machines, the arcuate path that the foot platforms travel about is a simple function of the distance between the foot platform and the pivot point of the platform support member. The stop and go motion of conventional steppers, in conjunction with the somewhat linear foot path, is considered by the inventor to be less ergonomic than the four bar stepper design of the present invention.
If one studies the motion paths of human feet during an activity such as walking or running, it will readily be observed that they travel along paths more accurately described as teardrop shaped. Whereas in the case of hill or stair climbing, the motion of ones feet closely resembles an ellipse or oval. The present invention provides a means to satisfactorily produce either motion, teardrop or elliptical, and does so in an efficient and economical way.